The Allow PHP Execute plugin for WordPress is vulnerable to PHP Code Injection in all versions up to, and including, 1.0. This is due to allowing PHP code to be entered by all users for whom unfiltered HTML is allowed. This makes it possible for authenticated attackers, with Editor-level access and above, to inject PHP code into posts and pages.
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.